Capping a day of solemn remembrance, thousands of paper lanterns representing the souls of those killed in the atomic attack on Hiroshima, Japan, 60 years ago have floated down the city's Motoyasu River.

Families and friends gathered along the banks of the river Saturday night to launch the candlelit lanterns. The river is the same one survivors fled to in an effort to escape the horrific heat of the nuclear blast.

The annual lantern observance brought to a close a full day of memorials, including official ceremonies at the Peace Memorial Park and dozens of peace rallies.

Thousands of residents, joined by Japanese and foreign dignitaries, bowed their heads at 8:15 a.m. - the exact moment of the attack - and offered prayers for world peace and for the souls of those who died in the blast.